Khan, who heads Pakistan Tehrik-e-Insaaf, said Britain was practicing 'double standards' in that it was fighting the international war against terrorism, but also sheltering Hussain, 'the number one terrorist of Pakistan'.

'The British government has shown double standards. On the one hand it is fighting a war against terrorism and on the other it has given citizenship to the number one terrorist of Pakistan,' he said.

The opposition parties have alleged that the MQM, having a strong presence in Karachi, had precipitated violence by wanting to stage a rally against suspended Chief Justice Iftikhar Mohammed Chaudhry who was visiting Karachi last Saturday.

Forty people have died in the violence.

Khan said that his party would file a case against Altaf Hussain in London.

'He is not representing Muhajirs, but running a fascist party.'

'We will hire lawyers' panel in London to file a suit against Altaf Hussain because he is responsible for the killing of innocent people in Karachi,' he said. Imran said that his party was also considering lodging an FIR against rulers for the bloodshed in Karachi.

Hussain, who has been in exile, living mostly in London, for the past many years, has been guiding the MQM speaking on telephone and video.

Khan has been a long-time critic of President Pervez Musharraf and is the only lawmaker of his party in the assembly.

The party's Punjab unit Monday urged Khan to resign from the National Assembly saying that parliament had not been able to 'protect rights of the citizens and suppression of the judiciary.'